Upgrading 50W head to 100W head?

[Nickerz]

I understand this may not be "worth it" rather than purchasing another head, but I'm considering this in the case of the Marshall 9005 which is only offered in 50W versions. I'm assuming that the scaling is straightforward and replacing the transformers would simply be specing them out. There also appears to be space to do so, and I wouldn't mind taking another rack space to deal with it if necessary, instead of having two JCM800 power slaves. So it'd be adding 4 tubes, replacing output transformers. But I'm just a gear geek, I've never built my own amp. And frankly I wouldn't do this myself. I'm just seeing if such a thing would be easily dealt with by an amp tech\modder.

[Davidg]

Hey! I just revived an old thread of yours with similar question. To be honest it would be far more trouble than it aould be worth and way more money than a 100 watt power amp IF it could be done and I dont think you would have the space to do it and you would have to change power transformer also$$ due to heater current. If you want a power amp that rezponds like a typical Marshall power section there are more than a few that will do that. Off the top of my head I'm thinking of the Carvin QuadX power amp. it is a bone stock JCM 800 power amp in rack form handmade in the USA and built like a tank, and I'm sure there are others. I would guess most any rackmount power amp from the 80s would be similar. If you must have 100 watts buy one of these and be done with it. Ic you want it to be driven by a signal hotter than line level have a tech put in a special line out on your amp (Freidman I think you stated previously?) that comes straight out of the tone stack and IF you turn it up loud enough to clip you will gdt all the tone characteristics of a clipping 100 watt power amp. Any tech could xo that very easily for a small fee. Heck ic you really want to clip it that bad take the line out off of the phase inverter and you will have an extra gain stage pushing the power amp. Have a tech look at it because the signal may be too hot and need to be padded down, (which kind of defeats the purpose of a line out off the PI ) but should be doable. That said I still think Reeltarted's answer in your previous post is the right one. Look at how the pro's do it- there is a reason that the majority of them do it the same way. And it is not just because "thats how Eddie does it". It's because it works and is the best way. What arenas are you going to be playiing in with 2 - 100watt amps clipping exactly? Because there is no way you can play any bar or club with that kind of volume.(not trying to be a smart a$$ I'm just not sure if you realize that) But if u must have this slave setup a Quad X or similar will get u there and has options of running in stero or mono and different impedance selections. It may be helpful if you could tell us what uou are wanting to do exactly? Stereo effecfs or wet/dry setup, wet/dry/wet or just need to peel some paint off the walls or shatter some windows? Literally trying to wake the dead perhaps? Lol

[pompeiisneaks]

Yeah DavidG is right, it takes a new OT at a minimum, and often a new PT or at least a new heater transformer to provide the extra power tubes heaters current (usually the main B+ can handle a fwe more milliamps of current there, but the heaters need a few more amps, I think typical power tubes are 600-900 mA per so you're looking at almost 2 A more current in the winding. Then you need space, and to drill the chassis, and add sockets etc. If it's a valuable amp that's a pretty destructive mod.

Totally doable, though, but is it worth it? Not sure.

~Phil

[Nickerz]

I'm trying to avoid buying two JCM800s that I'd have to turn into dedicated slaves is the main issue. It's $2000 plus its two heads that aren't really well suited to being slaved, so they'd need to be modified as dedicated slaves. So probably $3000 in and not in the format I'd want. Plus I've already started accumulating rack gear so it just makes sense, if possible. Can get a 9005 for $500 all day long and it's got two power sections. So even with a $1000-2000 in mods it'd be worth it to me (and still cheaper). Not to mention it's going to cost money to turn the JCM800s into a dedicated slaves. I've got an EL34 100\100 that is smooth, but I'm looking for something punchy with that same Marshall flavor now.

Looked into the QuadX but could only find the preamp. I want this to be real, but I've looked all across the web for a 100W JCM800 power section in rack form and never found it. And frankly I'm not sure if the 9005 is, I'm still working on verifying that. But I know almost certainly the 100\100 and 9200 are JCM900 power sections.

At this point I think it probably could be commissioned here and be a win for all parties, honestly.

[pompeiisneaks]

That makes sense, and yes I think someone here could do that pretty well. We've got quite a few marshal geniuses here .

~Phil

[Reeltarded]

Slave two heads. They are already built for it. You go in through the loop return.

Also not worth the hassle.

[Nickerz]

So i've got 3 schematics for those that can read. From what I can see the 9005 is related, but NOT a clone of the JCM800 50W power section. I'm curious what this 2001 power section reads like to you vets, because this is labelled as a JCM800 in the schematic! 375W JCM800!

What are the differences in the 9005 and the 50W jcm800? Or are they far enough from a schematic standpoint that they're from a different family? From what I can see the OT is unique, but why? The 9200 and 100\100, JCM900 etc share theirs....

[Reeltarded]

Yeah it has a driver set of stages and a different PI tail at a glance. It's the bass counterpart to the 9100.

Totally not worth it.

Bad idea to come here with a bad dream looking for reason. You have a rack you said. You have a head you like so much you want a slave. Buy an identical head and you have stereo output. There is no need for a dry middle. The stereo rig makes a virtual third channel out of the summed non-stereo components of the sound sources with two power sections and cabinets.

[Nickerz]

At that point it makes more sense to "Marshallize" a VHT 2100 Classic since two heads modified to be dedicated slaves with poweramp controls would run about $3000. Since you're considered the authority on this stuff, can you link me to content to understand what makes up the "voicing" in a poweramp? Alternatively I've seriously considered oversized transformers to get the punch my 2:90 and other big leagues have in my 100\100, what's your thoughts on that?

[Reeltarded]

What head are you using?

First off, they already made what yiu are asking about. The model 9200 is a dual 100w amplifier.

https://reverb.com/item/11840045-marsha ... w.ds&pla=1

There is one for a thousand dollars. Be aware that it uses idiot tubes (fake short 5881s) and two quads of real tubes won't fit under the lid.

It's not a good idea. Instead, pay $350 for a used Palmer PGA-04 in 8 OHM version and buy a sub-$500 class-D power amp. It's cheaper to buy a new power amp every year than to service and tube any of these things, and if you are using effects, then you can't really even drive the tubes into sing.. because, hey! Distorted reverb sounds like a boat load of shit!



Use Palmers. Use class-D. You can drive the crap out of your amp and your rig sounds like a produced version of itself with loads of headroom that sounds cranked even at television.. (or iphone) volumes.. because it is. I use a 2200 watt power amp and channelize several heads through a submixer with all the effects inserted there. It's configurable and as bulletproof as you can make a thing. With 2200w you can play a pair of cabinets in a jazz club and nobody gets pissed off as well as showing up at an outside festival with a quad of cabs and not be a slave to stupid modern monitoring rigs that give you a brain infection.

[Nickerz]

I already have the superior version, the EL34 100\100 and a Mesa 2:90. I run them in dual stereo from 4 modeller preamp outs. I don't use stereo effects. It's for the "stereo effect" in terms of amp grind. And since I'm masking the hard edges of modelling tone creating a hybrid tone (which I like with tubes) solid state 100% won't work here without power amp modelling. Also I don't know if there's any load boxes that can handle stuff like a Strategy 500.

There is an example of this setup you describe here.

https://www.youtube.com/watch?v=4wRTxBhqNuY

I still like Bolt Thrower's tone. This is dual stereo preamp outs into SS poweramps. But it's a dated sound.

This effect is best represented in these clips, I've got the timecodes. That is the distinct sound of one or two stereo preamp outs.

https://www.youtube.com/watch?v=5DLT6Ba ... tu.be&t=76

https://www.youtube.com/watch?v=xoa5iqn ... u.be&t=105

The tube warmth here is desired more or less. I'm just trying to bump up my poweramps a little more. The EL34 100\100 (evolution of the 9200) lacks the punch of the 2:90. I think I'm going to go VHT classic and 2150 and mod the tone circuits I guess. IDK, I'm looking for creative ideas, but I'm not going to ditch tubes because poweramp modelling isn't good. Preamp modelling is mature though. I'm done buying heads.